The present invention relates to a program, an information storage medium, and an image generation system.
An image generation system (game system) has been known which generates an image viewed from a virtual camera (given viewpoint) in an object space (virtual three-dimensional space) in which an object such as a character is disposed. Such an image generation system is very popular as a system which enables experience of so-called virtual reality.
In such an image generation system, it is desirable that a glare effect, which causes the outline of an object to be blurred due to light present behind the object, be realistically expressed in order to increase the virtual reality of the player.
A bright object or a bright area on the screen which produces glare is hereinafter called a “glare source”. An object subjected to glare is hereinafter called a “glare target object”. As expression which further increases the reality of an image using glare, the color of the glare target object positioned in front of the glare source (on the side of the viewpoint) may be made darker in the area subjected to glare. Such a dark expression is hereinafter called a “contrast”.
JP-A-2002-42156 and JP-A-2003-85578 disclose technologies for generating an image in which such a glare (glow or halo) effect is expressed, for example.
However, these technologies do not allow expression of the glare contrast. Therefore, a realistic expression of the glare effect cannot be sufficiently achieved.